The present invention relates to a camera with a film transport device for gradual advancement of a one-edge perforated light sensitive film over a picture gate and with a device for illuminating a mark on one edge of the film.
Cameras of the above-mentioned general type are known in the art. For example, one of such cameras is disclosed in the German Offenlegungsschrift 2,746,036. The marks serve for recognition of individual frames to be projected in immovable position. The arrangement for applying the mark includes an illumination station which is located after the picture gate on the perforation side as considered in direction of the film running. The marks are located in front of the respective frames on the film.
It has been recognized that the construction of the respective camera must satisfy different requirements with the consideration of the problems caused by the illumination and the projection. A particular difficulty is that the marking device must not be dirtied. Dirt can accumulate in the camera for example by the claw or by the film wear caused by film positioning means. Furthermore, the mark must be limited as great and accurate as possible so as to be easily and reliably detected by the respective detectors in the projection device. They must be not visible and projected over in any case.
As disclosed in the simultaneously filed application P 3030875.9 (CW 2434.0 PP/MP), the dirtying can be avoided in a construction in which the illumination device, particularly an opening with the associated light source, is arranged in front of the film transport device parts which cause wear, as considered in film running direction. It is possible in this construction to widen the film guide in such a manner that the illumination opening is edged in the film support plates and thereby sharp marks can be produced.
However, in this construction there can be not avoided that the dirt or dust settle in the illumination opening.